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Biomedical subjects

S Linder-Aronson

Publications and source records attributed to S Linder-Aronson.

At least 19 recordsLinked to original sources
PubMed1991

Mandibular and maxillary growth after changed mode of breathing.

The amount of maxillary and mandibular growth and the direction of maxillary growth were studied in 38 children during the 5 years after adenoidectomy for correction of severe nasopharyngeal obstruction. The amount of mandibular growth measured between successive gnathion points on superimposed radiographs was significantly greater in the group who had an adenoidectomy than in the matched controls. In the boys the difference was 3.8 mm (p less than 0.001), and in the girls the difference was 2.5 mm (p less than 0.01). The boys also showed a tendency toward greater growth in the maxilla as measured between successive subnasal points (1.2 mm, p less than 0.05). We detected no difference in the direction of maxillary growth between who had undergone adenoidectomy and the controls.

Adenoidectomy↗
PubMed1991

A morphometric study of bone surfaces and skin reactions after stimulation with static magnetic fields in rats.

The present investigation was undertaken to measure any bone surface changes after stimulation with orthodontic magnets and, furthermore, to examine the soft tissue in immediate contact with the magnets. Both distal parts of the tibial hind legs in six groups of young rats were fitted with devices holding two orthodontic magnets in the experimental legs and similar devices without magnets in the control legs. The animals were killed after 2, 3, and 4 weeks. Morphometric evaluation showed significant increases in resorbing areas after 3 and 4 weeks. Similarly, a reduction was evident in the number of epithelial cells under the areas where the magnets had been applied. These findings indicate that the stimulation of bone resorption in the present study may have been caused by inhibition of the bone-lining osteoblasts. This proposition is supported by the apparent inhibitory effect of the magnetic fields on epithelial recycling that was seen as a reduced thickness of the epithelium under the magnets. Consequently, static magnetic fields should be used with care in orthodontic practice until a more complete understanding of their mechanism of action has been established.

Animals↗
PubMed1991

Orthodontic and surgical treatment of unilateral condylar hyperplasia during growth--a case report.

A 9-year-old boy was diagnosed as having an unilateral cross-bite with mandibular deviation. This was later found to be due to unilateral hyperplasia of the right condyle. The increased growth activity subsequently led to an extreme facial asymmetry and a serious psychological condition began to develop. Consequently, surgery was performed at the age of 11 years 8 months when removal of the enlarged condyle and an oblique ramus osteotomy on the opposite side was performed. In this way the facial asymmetry was eliminated. No effort during the surgery was made, however, to restore normal occlusion. The post-operative orthodontic treatment was successful in allowing growth to bring about a normalization of the occlusal relationships. Two years after surgery, complete aesthetic and function rehabilitation has been achieved. This has also led to an improvement in the patient's psychological condition. The result was still stable 11 years post-operatively. The case illustrates the value of early treatment and co-operation between orthodontists and oral surgeons.

Age Factors↗
PubMed1991

Relationship between mandibular incisor crowding and nasal mucosal swelling.

In this study, cephalometric and dental cast variables relating to 30 male and 20 female children, 8 to 13 years old with chronic nasal mucosal swelling, were compared with those relating to age- and sex-method controls. These controls were orthodontically untreated subjects with no histories of airway obstruction. The children with chronic nasal mucosal swelling had been referred because of chronic difficulties with nasal breathing to the Department of Otolaryngology Airflow Laboratory at the Hospital for Sick Children in Toronto. Previously active posterior rhinomanometry with a head-out volume displacement plethysmograph had been used to measure nasal resistance in 1000 consecutive subjects. Participants in the study reported here were selected from subjects whose nasal resistance fell markedly following administration of a decongestant spray. The subjects selected were found to have significantly (p less than 0.001) more mandibular incisor crowding, significantly (p less than 0.01) smaller mandibular arch widths than the controls, and significantly (p less than 0.001) smaller maxillary arch widths than the controls. The male subjects had significantly (p less than 0.01) smaller mandibular arch widths than the male controls.

Adolescent↗
PubMed1991

Early interceptive treatment of asymmetry.

Severe asymmetry in pre-adolescent children usually arises either from congenital anomalies, such as unilateral condylar hypoplasia, or as a result of juvenile rheumatoid arthritis, condylar hyperplasia or early fracture of the mandible. Early surgical and orthodontic interceptive treatment of the asymmetry is important for normal development of the face and jaws.

Child↗
PubMed1990

Cranio-facial morphology in children with and without enlarged tonsils.

The purpose of the present study was to compare the cranio-facial morphology in children with and without enlarged tonsils. The material consisted of 73 children with enlarged tonsils, and a control group of children with normal tonsils, matched for age, sex, and number. The mean age for the groups was 10.1 and 10.0 years, respectively. Evaluation of anamnestic history, clinical examination, and lateral skull radiographs were undertaken. Compared to the control children, the children with enlarged tonsils had more retrognathic and posteriorly inclined mandibles, larger anterior total and lower facial heights, and larger mandibular plane angles. Regression analyses revealed that functional, postural, and morphological factors, such as open mouth posture, low posture of the tongue, large depth of oropharynx at the site of the tonsils as well as mouth-breathing at night, were associated with skeletal features expressing an increased open vertical configuration and mandibular retrognathism.

Cephalometry↗
PubMed1990

Titanium implant anchorage in orthodontic treatment an experimental investigation in monkeys.

Tooth loss can be a problem when orthodontic appliances have to be stabilized for treatment. It has been shown that endosseous titanium implants are well integrated during treatment of edentulous patients with intra-osseous anchored bridges. In the present investigation titanium implants were inserted immediately after tooth extraction. After tissue-integration of the implants they were successfully used for anchorage when orthodontic treatment was performed. In a clinical situation the implants may simultaneously be used for reconstruction of the bite.

Alveolar Process↗
PubMed1990

Posture of the head, the hyoid bone, and the tongue in children with and without enlarged tonsils.

The purpose of this investigation was to analyse whether there were any differences between children with and without enlarged tonsils with regard to the posture of the head, the hyoid bone, and the tongue. Twenty-two children with enlarged tonsils were compared with a matched normal control group. Of the children in the tonsil group, 59 per cent were mouth-breathers during the day and 82 per cent during the night. None of the control children was a mouth-breather. The results showed that, compared with the control children, children with enlarged tonsils had an extended posture of the head, a lowered position of the hyoid bone, and an antero-inferior posture of the tongue. The vertical position of the hyoid bone also reflected the vertical position of the tongue. The antero-posterior position of the tongue was closely related to the oro-pharyngeal depth. The postural pattern in children with enlarged tonsils appears to be associated with the need for maintenance of free oro-pharyngeal airway capacity.

Adolescent↗
PubMed1989

Mandibular form and position related to changed mode of breathing--a five-year longitudinal study.

A five-year follow-up study was performed on 26 children treated for nasal obstruction by adenoidectomy, who exhibited a changed mode of breathing postoperatively. They were compared with a control group matched according to age and sex. Lateral skull radiographs were used to examine mandibular morphology. The mandibular outline was registered using 36 digitized points. This method of portraying growth changes provides a valuable complement to isolated measurements. The technique revealed a more anterior direction of symphyseal growth in the adenoidectomy group following surgery as well as some reversal of the initial tendency to a posterior rotation of the mandible.

Adenoidectomy↗
PubMed1989

Dentition in children with enlarged tonsils compared to control children.

The aim of the present study was to evaluate whether or not there are any differences in the dentition between children with enlarged tonsils and those with normal tonsils. A sample of 73 children (33 boys and 40 girls) with enlarged tonsils and with a mean age of 10.1 years was compared with a normal control group, matched for age and sex. Eighteen dentition variables and thirty-two variables in anamnestic, clinical, pharyngeal and postural findings were recorded. Measurements were obtained from lateral skull radiographs and dental casts. Group means were compared. Relationships between variables were studied using simple correlations and multiple stepwise regression analyses. It was found that children with enlarged tonsils had more retroclined lower incisors, more anteriorly positioned upper incisors, smaller overbite, larger overjet, shorter lower dental arches, narrower upper dental arches and an increased frequency of lateral crossbite. Functional and/or morphological disorders, causing an open posture of the mouth, a lowered anterior posture of the tongue and a low position of the hyoid bone are thought to be associated with the differences in the dentition between the two groups. Obstruction of the oropharynx by enlarged tonsils, might be one factor responsible for these dysfunctions.

Adenoidectomy↗
PubMed1986

Mandibular growth direction following adenoidectomy.

The purpose of this article is to test the hypothesis that the establishment of nasal respiration in children with severe nasopharyngeal obstruction can be eliminated as a factor in determining mandibular growth direction. The article describes the changes in mandibular growth direction (MGD) in a 5-year period after adenoidectomies and the establishment of nasal breathing in a population of Swedish children. Measurements of mandibular growth directions were obtained from serial cephalometric radiographs after adenoidectomies in 38 Swedish children aged 7 to 12 years with previous nasopharyngeal obstructions. These were compared with the growth directions in a control sample of 37 Swedish children with clear airways and matched for age and sex. The adenoidectomy sample initially showed significantly longer lower face heights, steeper mandibular plane angles, and more retrognathic mandibles than the matched controls. Analysis showed that during the 5 years after adenoidectomies, the girls had a more horizontal MGD (P less than 0.02) than did the female controls. A corresponding but not significant trend was found for the boys. The individual growth directions that were obtained following adenoidectomies were more variable than those found in the controls.

Adenoidectomy↗